In some roofing installations, a membrane is adhered over top an existing and aging roof. This saves the effort, time, and money associated with demolishing the existing roof and disposing of its remains, and in this way presents a more environmentally sustainable alternative. The existing roof commonly includes a roof deck made of concrete, wood, or metal, and includes several layers on top of the roof deck containing a mix of asphalt, insulation, heavy felt paper, and/or granules. Still, existing roofs can include other constructions. Before a membrane is adhered to an existing roof, however, the existing roof should be inspected to be sure that it is suitable for repurposing and need not be replaced altogether. Part of that inspection typically involves determining the strength and structural integrity of the existing roof and that of an adhered joint between the membrane and an exposed surface of the existing roof.
Pull-testing is the usual procedure employed to observe these strengths and structural integrities. A test area of the existing roof is prepared with a sample membrane adhered to the exposed surface and a piece of wood adhered over the membrane. A pull-test frame is placed on the existing roof at the prepared test area. A pull plate is attached to the piece of wood, and a connected chain leads from the pull plate to a puller and a pressure reader set on an upper part of the frame. The puller draws the pull plate upward with force directed away from the existing roof until failure occurs. The construction of the existing roof can come apart, or the sample membrane can be pulled off of the exposed surface. Whichever occurs first, the pressure reader determines and displays the pressure value at which failure took place.
To date, the pull-test frames can be bulky and unwieldy, and are not always easily carried to the test area and assembled together.